Etymology: from bi (as in “life”) + onics (as in “electronics”); the study of mechanical systems that function like living organisms or parts of living organisms

Photograph by Robert Clark

Aiden Kenny, who would later receive cochlear implants in both ears, peers out the window of his home while his mother, Tammy Kenny, watches him. Because Aiden got the implants at a young age, he has a good chance of developing clear speech, his doctor says.

Photograph by Mark Thiessen

Wired for SoundAiden Kenny got two cochlear implants when he was ten months old. Bypassing parts of his ears that don't work, the implants—visible in an x-ray—carry electronic signals to his auditory nerves. Within months of the surgery, a child who’d grown increasingly quiet spoke the words his hearing parents longed for: Mama and Dada. “You’re looking at a real bionic kid,” says Johns Hopkins University surgeon John Niparko.

Aiden Kenny reacts to a sudden wave of unfamiliar sound by pointing to his ear at the moment his audiologist switches on one of his cochlear implants. His mother, Tammy Kenny, had taught him to react to sounds this way when he wore hearing aids. The implants, however, are much more effective in helping children distinguish the sounds of conversation.

Photograph by Max Aguilera-Hellweg

New VisionEyelids stretched wide under anesthesia, Jo Ann Lewis, 79, received new hardware in and around her eyeball, which works with a computer to transmit imagery to her brain. Electronics circumvent damaged light-receptor cells and give the blind Texan back a vestige of vision—shimmering lines, vague shapes, washes of color. “I don’t see like you see,” she says. “We’re on the ground floor of this technology.”

Photograph by Second Sight Medical Products

Each dot on an array tacked to a patient’s retina is an electrode that sends visual stimuli to the optic nerve, visible as a white circle at far right. Built by the U.S. company Second Sight, the one-third-inch-wide array has 60 electrodes. An older model had just 16. As with digital camera pixels, more electrodes capture more detail. The company is now developing implants with hundreds, even thousands, of electrodes.

Photograph by Max Aguilera-Hellweg

Familiar SightUsing her new bionic vision, Jo Ann Lewis recognizes objects she knew before losing her sight, though they’re blurry and vague. With practice, and her brain’s natural learning ability, objects should be more recognizable.

Photograph by Max Aguilera-Hellweg

Some of the parts in a bionic hand being developed by inventor Dean Kamen are off-the-shelf rather than custom designed and fabricated. Sponsored by the U.S. Army Research Office, Kamen has worked to create an upper-limb prosthesis that offers a sophisticated range of movement without requiring surgery.

Photograph by Mark Thiessen

Doctors and lab personnel attach sensors to tiny ink dots on Kitts’s residual arm in order to measure how her muscles respond to her attempts to control them. Unlike the simpler task of fitting the prosthesis, which has only a handful of sensors, this setup can take hours.

Photograph by Mark Thiessen

Mind and MachineAn array of sensors tracks muscle movements that Amanda Kitts produces in her residual arm thanks to surgically rerouted nerves. Next-generation prostheses obey relayed signals, increasingly working like her original limb.

Photograph by Mark Thiessen

Bionic WomanKitts imagines a hand movement, and muscle activity in her residual arm—decoded by a computer on her back—causes the actual motion. When she straps on the experimental Johns Hopkins-developed arm at the Rehabilitation Institute of Chicago, she says, “often it feels like I’m not missing anything.”

Photograph by Mark Thiessen

Amanda Kitts laughs as she squirts too much mustard onto bread while learning to use an advanced prosthesis. A surgery pioneered by Todd Kuiken at the Rehabilitation Institute of Chicago realigned nerves throughout the muscles in Kitts’s stump. Those nerves allow her to control the prosthesis, once she learns to control her muscles, and once the computer running the prosthesis is programmed to respond correctly to her moves.

Photograph by Mark Thiessen

The Proto 1 arm developed by the Johns Hopkins University Applied Physics Laboratory gives amputee Amanda Kitts enough fine motor control that she can pick up very small objects, like a key resting on the edge of a table.

Staying in StepMotorized springs in a powered ankle push off like a real leg, saving energy and easing joint problems. “Military amputees are young and athletic,” says designer Tom Sugar (at right), an Arizona State University engineering professor. “They want back all the function they had.”